diff --git a/ChangeLog b/ChangeLog
index c7b787ba73..7bfc20419c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Nov 20 20:54:01 2013  Masaya Tarui  <tarui@ruby-lang.org>
+
+	* tool/instruction.rb : fix typo.
+
 Wed Nov 20 19:45:22 2013  Tanaka Akira  <akr@fsij.org>
 
 	* random.c (rand_init): Make it possible to specify arbitrary array
diff --git a/tool/instruction.rb b/tool/instruction.rb
index 9dbc3ae6b8..0e992e02c6 100755
--- a/tool/instruction.rb
+++ b/tool/instruction.rb
@@ -816,7 +816,7 @@ class RubyVM
       commit  "  POPN(#{@popn});" if @popn > 0
     end
 
-    def make_hader_debug insn
+    def make_header_debug insn
       comment "  /* for debug */"
       commit  "  DEBUG_ENTER_INSN(\"#{insn.name}\");"
     end
@@ -869,7 +869,7 @@ class RubyVM
       make_header_stack_pops insn
       make_header_temporary_vars insn
       #
-      make_hader_debug insn
+      make_header_debug insn
       make_header_pc insn
       make_header_popn insn
       make_header_defines insn